Here is my test setup for the new electronics that will eventually run my Little Red Rover. The battery on the left powers all the electronics, including the Feather M0 Express (the MCU) and DC Motor Controller FeatherWing stacked at the top of the large breadboard. The battery on the right goes through a PowerBoost 1000C to provide 5V for the motors. The left and right VL53L0X distance sensors are on the small breadboard, connected to a TCA9548A I2C Multiplexer which is connected to the MCU using I2C. There is also an SHT31-D Temperature and Humidity sensor next to the MCU on the large breadboard. Both batteries are 3.7V @ 2500mAH Lithium Polymer packs.
Unfortunately, I can not load all the libraries I need all at once on the MCU because it only has 32Kb of RAM. I will have to wait until I can get a Feather HUZZAH ESP32, which has 520Kb of RAM so I can load everything I need. There are currently five different libraries I need for my Little Red Rover, and may be another one if I decide to put a pan/tilt on the front with a camera. That will require an 8-Channel PWM or Servo FeatherWing and associated library.
I have modified the DC Motor Controller library so it plays nice with other libraries and will use a shared I2C bus. With enough RAM and a different MCU, I should be able to use whatever libraries I need for my rover,